The present invention relates to new fat mimetic compounds and their uses in edible compositions. These compounds comprise a backbone to which is attached one fatty --CO.sub.2 R' (carboxylate) group and one fatty --O.sub.2 C--R' (carboxy) group. In one embodiment, carboxy/carboxylate disubstituted esters are partially digestible.
Obesity is perceived as a common problem in contemporary society. This condition is due, in many people, to a greater intake of calories than are expended. While genetic and behavioral factors play a major role, it is generally agreed that reasonable modifications of the caloric value of foods can be valuable in reaching a desirable equilibrium weight for an individual predisposed to obesity.
Many foods which provide gustatory satisfaction contain significant fat levels. This can be a problem for individuals drawn to these foods because fat has about twice the caloric density of protein and carbohydrates. It has, in fact, been estimated that fat contributes about 40% of the total calories in the diet. It has long been desired to reduce the available calories of dietary fat without decreasing the appeal or satiety expected of fatty foods. It has been reported that this would offer a convenient and practical method by which obesity could be controlled, ideally without requiring a dieter to restrict total food intake.
A reduction in fat content has been suggested for other reasons as well. Certain fats appear to pose a health risk when consumed in large quantities over time. Moreover, the amount of fat in the American diet has increased in the last 60 years by about 25% (Mead, J., et al Lipids, Plenum, N.Y., 1986, page 459). A number of national advisory committees on nutrition have presented their findings which differ in detail, but share as a common point the recommendation of reducing the total amount of fat in our diet (Gottenbos, J.J., chapter 8 in Beare-Rogers, J., ed., Dietary Fat Requirements in Health and Development, A.O.C.S. 1988, page 109). Hence, major research efforts have focused on ways to produce food substances that provide the same functional and organoleptic properties as fats, but not the calories.
A number of fat replacements have heretofore been suggested (recently reviewed by Hamm, D.J., 49 J. Food Sci. 419-428 (1984), Haumann, B.J., 63 J. Amer. Oil Chem. Soc. 278-288 (1986) and LaBarge, R.G., 42 Food Tech. 84-90 (1988). Hamm divides replacement fats into two broad categories: structurally re-engineered triglycerides modified to retain their conventional functional properties in foods, while removing their susceptibility toward hydrolysis or subsequent absorption during digestion, and materials developed from chemistry unrelated to triglycerides.
Examples of the former class of triglyceride analogues include compounds having the glycerol moiety replaced with alternate polyols (e.g., pentaerythritol in U.S. Pat. No. 2,962,419 to Minich, or sugars, suggested by Hess, K., and Messmer, E., 54B Ber. 499-523 (1921), and patented years later by Mattson and Volpenhein, U.S. Pat. No. 3,600,186, and Meyer, et al., U.S. Pat. No. 4,840,815); compounds having the fatty acids replaced with alternate acids (e.g., branched esters as described in U.S. Pat. No. 3,579,548 to Whyte); compounds having insertions between the glycerol and the fatty acid (e.g., ethoxy or propoxy groups in U.S. Pat. No. 4,861,613 to White and Pollard); compounds having reversed esters (e.g., malonates in U.S. Pat. No. 4,482,927 to Fulcher and trialkoxytricarballylates in U.S. Pat. No. 4,508,746 to Hamm); and compounds having the ester bonds replaced by ether bonds (Can. Pat. No. 1,106,681 to Trost).
Related to triglyceride analogues are dimeric fat replacements. Thirty years ago, the U.S.D.A. assessed the caloric availability and digestibility of a series of new-type fats, including dibasic acid-bridged diglycerides (specifically, fumaric, succinic and adipic-bridged diglyceride esters; see Feuge, R.O., and Ward, T.L., 80 J. Amer. Chem. Soc. 6338-6341 (1958); Ward, T.L., et al. 36 J. Amer. Oil Chem. Soc. 667-671 (1959); Feuge, R.O., and Ward, T.L., 37 J. Amer. Oil Chem. Soc. 291-294 (1960); and Shull, R.L., et al. 38 J. Amer. Oil Chem. Soc. 84-86 (1961)). Minich suggested ether-bridged dipentaerythritol esters about the same time (U.S. Pat. No. 2,962,419, column 53 to 76), although he exemplified only pentaerythritol ester monomers.
Examples of Hamm's second category of fat replacements chemically unrelated to triglycerides are mineral oil (suggested as early as 1894 in U.S. Pat. No. 519,980 to Winter); polyglucose and polymaltose (U.S. Pat. No. 3,876,794 to Rennhard); jojoba wax (W. Ger. Pat. No. 3,529,564 to Anika); polyoxyalkylene esters (U.S. Pat. No. 4,849,242 to Kershner); polyvinyl alcohol esters (U.S. Pat. No. 4,915,074 to D'Amelia and Jacklin); and polysiloxane (Eur. Pat. Ap. No. 205,273 to Frye).
Nondigestible or nonabsorbable edible fat replacements have proved disappointing when tested in feeding trials, where gastrointestinal side effects occurred, in some cases so extreme that frank anal leakage was observed. Nondigestible fats appear to act as a laxative and are expelled from the body, eliciting foreign body reactions like those early documented for mineral oil (Stryker, W.A., 31 Arch. Path. 670-692 (1941), more recently summarized in Goodman and Gilman's Pharmacological Basis of Therapeutics, 7th ed., Macmillan Pub. Co., N.Y. 1985, pp. 1002-1003). Similarly, experimental fats synthesized by the U.S.D.A group mentioned above exhibited undesirable gastrointestinal side effects when the compounds were fed to rats (Booth, A.N., and Gros, A.T., 40 J. Amer. Oil Chem. Soc. 551-553 (1963)); in several of the balance studies, the diarrhea was so extreme that digestibility coefficients could not be calculated (ibid., Table I, p. 552).
Polyglycerol and polyglycerol esters, suggested as fat replacements by Babayan and Lehman (U.S. Pat. No. 3,637,774), have been suggested for use as fecal softening agents as well (U.S. Pat. No. 3,495,010 to Fossel). A number of remedies have been recommended to combat the anal leakage observed when sucrose polyesters are ingested (e.g., employing cocoa butters, U.S. Pat. No. 4,005,195 to Jandacek, incorporating saturated fatty groups, Eur. Pat. Ap. No. 233,856 to Bernhardt, or mixing residues, U.S. Pat. No. 4,797,300 to Jandacek, et al.), and dietary fiber preparations have been incorporated into polysaccharide and/or polyol-containing foodstuffs to help inhibit the diarrheal effect (U.S. Pat. No. 4,304,768 to Staub et al.). Partially digestible fat replacements have also been suggested (U.S. Pat. No. 4,830,787 to Klemann and Finley, which is fully incorporated herein by reference, and U.S. Pat. No. 4,849,242, cited above).